阅读说明：本技术 适于焊接的用于车辆燃料储箱的管道 (Pipe for a fuel tank of a vehicle, suitable for welding ) 是由 奥雷利安·加泰 卡米耶·德维勒斯 于 2018-06-12 设计创作，主要内容包括：本发明涉及一种用于制造车辆燃料储箱管道(2)的方法,在该方法中：在模具中模制壁,该壁包括由乙烯-乙烯醇(EVOH)制成的内层(6)和由适于焊接的聚合物制成的外层(8),所述模具包括至少一个在所述模制时在所述壁的端部部分的外表面上产生至少一个公肩部的母肩部,然后,切割所述壁的该端部部分。(The invention relates to a method for manufacturing a vehicle fuel tank pipe (2), in which method: -moulding a wall comprising an inner layer (6) made of ethylene vinyl alcohol (EVOH) and an outer layer (8) made of a polymer suitable for welding in a mould comprising at least one female shoulder that, when said moulding, produces at least one male shoulder on the outer surface of an end portion of said wall, then cutting this end portion of said wall.)

1. A method for manufacturing a pipe (2) of a vehicle fuel tank (24), characterized in that:

moulding a wall comprising an inner layer (6) made of ethylene vinyl alcohol (EVOH) and an outer layer (8) made of a polymer suitable for welding in a mould (14) comprising at least one female shoulder (18) which, when moulded, forms at least one male shoulder (12) on the outer surface of an end portion of the wall, after which,

the end portion of the wall is cut.

2. The method according to claim 1, wherein the cutting step is carried out parallel to a main axis (4) of the pipe (2).

3. A method as claimed in claim 1, wherein the angle is non-zero along a main axis (4) relative to the pipe (2).

4. Method according to claim 3, wherein said cutting step is carried out along an angle of less than 60 °, preferably less than 30 °, with respect to said main axis (4).

5. The method of any of the preceding claims, wherein the female shoulder (18) of the mold (14) is formed by an insert (16), which is optionally removable.

6. A method as claimed in any one of the foregoing claims, wherein said moulding step is carried out by blow-moulding said wall in said mould (14).

7. A method for manufacturing a fuel storage system, characterized by:

-manufacturing a pipe (2) according to the method of any one of the preceding claims; and

welding the end (10) of the pipe (2) to a fuel tank (24).

8. -pipe (2) for a fuel tank of a vehicle, characterized in that it comprises a wall comprising an inner layer (6) made of ethylene-vinyl alcohol (EVOH) and an outer layer (8) made of a polymer suitable for welding, the axial end portions of said pipe (2) being formed of said polymer suitable for welding, the outer diameter of said pipe (2) at the end portions (10) being smaller than or equal to the outer diameter of a middle portion (11) of said pipe (2).

9. A pipe (2) as claimed in claim 8, wherein the end portion (10) has an outer diameter which is smaller than or equal to the outer diameter of the portion of the pipe adjoining the end portion (10).

10. Mould (14) for manufacturing a vehicle fuel tank pipe, characterized in that it comprises at least one female shoulder (18) arranged to produce, when moulding a wall, at least one male shoulder (12) on the outer surface of an end portion of said wall.

11. The mold (14) of claim 10, wherein the female shoulder (18) is formed by an insert (16) that is optionally removable.

Technical Field

The present invention relates to a vehicle fuel tank. More specifically, the invention relates to a pipe for a fuel tank of a vehicle suitable for welding.

Background

Vehicle fuel storage systems generally include a tank in which fuel is stored. To which a plurality of accessories or elements implementing different functions are fixed. Soldering/welding (soud) is a fixing process often chosen for this purpose. One of the elements fixed by welding is in particular a pipe for supplying the tank with fuel.

It is known to provide the wall of a pipe with an impermeable layer on the inside of the pipe, which layer has the function of increasing the impermeability of the pipe. This allows to reduce the risk of leakage of the gas or fuel flowing in the pipe. The material generally selected for the barrier layer is ethylene vinyl alcohol (EVOH). However, the properties of the polymer are not compatible for welding to the tank. This is why the walls of the pipes are generally multi-layered, comprising a barrier layer and a polymer layer suitable for welding.

In order to create an interface of sufficient area for welding and sufficient polymer thickness on the pipe side for welding, there are several solutions.

A first solution consists in adding a piece, for example a wing, at the end portion of the pipe to be welded to the tank. The wings provide additional area to the pipe/tank interface and can be made of a polymer suitable for welding. However, the installation of the wing results in additional costs and additional steps in the fixing process, so that the solution is preferably not used.

A second solution consists in axially compressing a portion of the pipe when it is moulded. Thereby, a flange is created on a portion of the pipe. If the flange is located at the end of the pipe, the arrangement of the layers of the wall of the pipe allows to form a polymer thickness suitable for welding in the main direction of the pipe. In other words, the EVOH is kept away from the axial end of the pipe. Whereby the end of the pipe can be welded to the tank. However, the creation of the flange requires the handling duct to move as it is being molded. This operation may be critical and not necessarily well mastered, which is detrimental to the repeatability of the tube fabrication. Moreover, this movement constitutes an additional operation in the fixing process, which complicates the fixing process.

Furthermore, both solutions have the common additional drawback of locally increasing the diameter of the pipe. Depending on the shape and size of the fuel tank, this may constitute a limiting factor. Therefore, it is preferable to avoid increasing the volume of the pipe.

Disclosure of Invention

One purpose of the present invention is to remedy the above drawbacks and to propose a compact pipe suitable for welding and easy to implement.

To this end, according to the invention, a method is provided for manufacturing a vehicle fuel tank pipe, in which method:

-moulding a wall comprising an inner layer made of ethylene vinyl alcohol (EVOH) and an outer layer made of a polymer suitable for welding in a mould comprising at least one female shoulder which, when moulded, produces at least one male shoulder on the outer surface of an end portion of the wall, and then,

-cutting the end portion of the wall.

Hereby, thanks to the cutting of the end portion of the pipe and to the arrangement of the layers of the wall, a polymer thickness suitable for welding is produced in the main direction of the pipe, in a manner similar to the flanges of the prior art in which EVOH is remote from the end of the pipe.

The step of cutting the end portion allows the overall shape of the pipe to be unaltered while maintaining suitable weldability provided by the shape imparted to the pipe in the die. Furthermore, the formation of the male shoulder of the wall of the duct is done passively at the time of moulding. Thus not complicating the manufacturing process of the duct.

Furthermore, the step of moving the walls in the mould (used in the prior art for producing the flanges) is eliminated, which is the source of the loss of repeatability in the manufacture of the tubes.

Finally, in contrast to the two prior art solutions described above, the shape of the female shoulder and the cutting step are such as not to locally increase the outer diameter of the pipe. This drawback is therefore also overcome.

According to a first embodiment of the invention, the cutting step is carried out parallel to the main axis of the pipe.

According to a second embodiment of the invention, the cutting step is carried out along a non-zero angle with respect to the main axis of the pipe.

Preferably, the cutting step is carried out along an angle of less than 60 °, preferably less than 30 °, with respect to the main axis.

Thus, a plurality of cutting methods can be considered. This helps to make the manufacturing method of the pipe flexible and adaptable to the manufacturing facilities available. If the cutting step is carried out along a non-zero angle relative to the main axis of the duct, it is preferred to select this angle as small as possible to limit a reduction in the inner diameter of the duct, which reduction may adversely affect the filling performance of the duct.

Advantageously, the female shoulder of the mould is formed by an insert, which is optionally removable.

Conventional dies can also be easily modified to allow for the formation of the male shoulder of the wall of the conduit. By having the insert removable, the shape of the female shoulder and thus the shape and size of the male shoulder of the conduit can be easily changed.

Advantageously, the moulding step is carried out by blow moulding said wall in a mould.

Blow molding is a well-understood operation and is suitable for the present invention.

According to the present invention, there is also provided a method for manufacturing a vehicle fuel storage system, in which method:

-manufacturing a pipe according to the method as described above; and

-welding said end of the pipe to the fuel tank.

According to the invention, there is also provided a pipe for a fuel tank, comprising a wall comprising an inner layer made of ethylene vinyl alcohol (EVOH) and an outer layer made of a polymer suitable for welding, an axial end portion of the pipe being formed of a polymer suitable for welding, the outer diameter of the pipe at the end portion being smaller than or equal to the outer diameter of a middle portion of the pipe.

Advantageously, the outer diameter of the end portion is smaller than or equal to the outer diameter of the portion of the pipe adjoining the end portion.

It is thereby ensured that the outer diameter of the pipe is not locally increased at the welding location, which allows to avoid the creation of useless volumes.

According to the invention, there is additionally provided a mould for manufacturing a pipe for a fuel tank of a vehicle, comprising at least one female shoulder arranged to produce at least one male shoulder on the outer surface of an end portion of the wall when the wall is moulded.

Advantageously, the female shoulder is formed by an insert, which is optionally removable.

Drawings

An embodiment of the invention will now be described based on the accompanying drawings, in which:

figure 1 is a longitudinal section of a vehicle fuel tank pipe according to a first embodiment of the invention;

figure 2 shows a cutting step of the manufacturing method of the pipe of figure 1;

figure 3 shows an end portion of the pipe of figure 1 after the cutting step;

figure 4 shows an end portion of a pipe for a vehicle fuel tank according to a second embodiment of the invention;

FIG. 5 is a schematic view showing a mould comprising a female shoulder (Lepaul element) suitable for implementing the manufacturing method according to the invention;

figure 6 is a schematic view showing the pipe of figure 1 welded to a fuel tank; and

figure 7 is a cross-section of the pipe shown in figure 6 welded to the tank.

Detailed Description

In fig. 1 a pipe 2 according to a first embodiment of the invention is shown. The pipe 2 has a main axis 4. In the present example, the pipe 2 has at least partially a cylindrical shape, but it is conceivable that the pipe has any other shape.

The pipe 2 comprises a wall which itself comprises a plurality of layers. In this example, it comprises an inner layer 6 and an outer layer 8 radially superposed on a large portion of the pipe 2.

The inner layer 6 is made of a so-called impermeable material which allows to reduce the permeability of the pipe 2. It is made here from ethylene vinyl alcohol (EVOH). However, any other barrier material having similar properties to EVOH may be selected.

The outer layer 8 is made of a polymer suitable for subsequent welding of the pipe 2 to the fuel tank. Such polymers are well known to those skilled in the art. May for example be high density Polyethylene (PEHD).

"inner layer 6" refers to the layer located radially below outer layer 8. In other words, the inner layer 6 is not exposed on the radially outer surface of the pipe 2. The inner layer 6 may be formed of a plurality of layers comprising different materials. For example, a six-or seven-layer wall structure may be provided comprising, in order from the inside of the pipe: a conductive layer consisting of conductive PEHD, optionally an intermediate layer made of PEHD, an adhesive layer, a barrier layer made of EVOH, an adhesive layer, an intermediate layer, and finally a decorative layer of black PEHD. In this example, in the sense of the present invention, the black PEHD trim layer forms an outer layer and the whole of those five or six other layers forms an inner layer. Thus, the inner layer is partly realized by EVOH.

In the following, for the sake of convenience in describing the invention, it will be considered that the wall comprises only two layers, namely an outer layer 8 and an inner layer 6 made entirely of EVOH.

The pipe 2 has an axial end 10 suitable for welding of the pipe 2. The other end of the pipe 2 is not shown and will not be described, since a description thereof is not necessary for understanding the invention. As can be seen in fig. 1, the end portion 10 of the pipe is formed from a polymer suitable for welding. The pipe 2 can thus be easily welded at this end 10, since EVOH is not present in the end portion 10 (which is a material that is not compatible with welding).

Still visible in fig. 1, the outer diameter of the pipe 2 at the end portion 10 is smaller than or equal to the outer diameter of the middle portion 11 of the pipe 2. The outer diameter of the end portion 10 is here smaller than or equal to the outer diameter of that part of the pipe which adjoins the end portion 10. The inner layer 6 and the outer layer 8 are radially superposed throughout the middle portion 11 of the pipe 2. Here, the outer diameter of the pipe 2 at the end portion 10 is approximately equal to the diameter of the intermediate portion 11. The intermediate portion 11 of the pipe 2 is located beyond its two axial end portions.

These characteristics of the conduit are of interest for reasons that will be explained later in this application.

A pipe manufacturing method according to a first embodiment will now be described.

Referring to fig. 5, a wall comprising a layer made of EVOH and a layer made of a polymer suitable for welding is first molded in a mold 14 allowing blow molding.

The mold 14 includes two mold portions 14a and 14b, each of which carries a portion of the insert 16. The insert forms a female shoulder 18 in the mould, the female shoulder 18 being provided to form at least one male shoulder 12 on the outer surface of the end portion of the wall during moulding. Once the moulding is terminated, the wall is shaped in the shape of the duct 2.

After moulding, the end portion 10 of the pipe 2 is cut. As can be seen in fig. 2, the cut is made parallel to axis 4 along arrow 20. Thereby, the part of the end portion 10 having the male shoulder 12 is taken away from the pipe 2. It is due to this cutting that the remaining part of the end portion 10 of the pipe 2 is entirely formed of a polymer suitable for welding. This is visible on a larger scale in fig. 3.

According to a second embodiment of the invention, illustrated in figure 4, the cut is not parallel to the axis 4, but the cut of the end portion 10 is made along the cutting line 22 according to a non-zero angle α with respect to the axis 4. The angle alpha is less than 60 deg., and in fig. 4 is approximately equal to 45 deg.. However, it is preferred that the angle α is less than 30 °. As in the first embodiment, the remainder of the end portion 10 of the pipe 2 is formed from a polymer suitable for welding.

In fig. 6 a fuel tank 24 belonging to a fuel storage system of a vehicle according to the invention is shown. The memory system is manufactured according to the following method:

-manufacturing the pipe 2 according to a method according to either of the two embodiments, complying with the above, and then,

welding the end portion 10 of the pipe 2 to the tank 24.

Since the end portion 10 of the pipe 2 is formed of a polymer suitable for welding, welding can be performed directly without the need to prepare the pipe 2 or the tank 24 for this purpose.

Moreover, this allows the end portion 10 of the tube 2 to retain a shape similar to that of an identical filling tube not comprising an EVOH layer, without the end portion needing to be specifically adjusted for this purpose, and having a constant outer diameter.

Moreover, the fact that the diameter of the wall of pipe 2 at end portion 10 is smaller than or equal to the outer diameter of middle portion 11 of the wall makes it possible to weld pipe 2 in a port or groove 26 provided in the wall of tank 24. As can be seen in fig. 7, the constant or decreasing outer diameter of the pipe 2 towards the end 10 allows it to conform to the shape of the groove 26. This also allows the operation of the inlet valve 28 located in the tank 26 to be unimpeded. The valve 28 is generally referred to by the english term "let check valve" (ICV).

Of course, many modifications may be made to the present invention without departing from its scope.

The invention is also applicable to welding the pipe to a pipe head. In practice, the second end of the pipe may be welded to such a pipe head. The embodiment of the invention described above is still applicable if tank 24 and its tank 26 are replaced by a tube head.